Merge remote-tracking branch 'remotes/cleber/tags/python-next-pull-request' into staging

Improvements include:

 * Relaxed error code pattern on machine_m68k_nextcube.py
 * Better naming and separation of tests in x86_cpu_model_versions.py
 * New checks on guest side on linux_ssh_mips_malta.py
 * Use of avocado.utils.ssh, and thus "/usr/bin/ssh" for SSH
   interaction

# gpg: Signature made Mon 23 Sep 2019 14:38:01 BST
# gpg:                using RSA key 7ABB96EB8B46B94D5E0FE9BB657E8D33A5F209F3
# gpg: Good signature from "Cleber Rosa <crosa@redhat.com>" [marginal]
# gpg: WARNING: This key is not certified with sufficiently trusted signatures!
# gpg:          It is not certain that the signature belongs to the owner.
# Primary key fingerprint: 7ABB 96EB 8B46 B94D 5E0F  E9BB 657E 8D33 A5F2 09F3

* remotes/cleber/tags/python-next-pull-request:
  Acceptance tests: use avocado.utils.ssh for SSH interaction
  tests/acceptance: Add new test cases in linux_ssh_mips_malta.py
  tests/acceptance: Refactor and improve reporting in linux_ssh_mips_malta.py
  Acceptance test x86_cpu_model_versions: split into smaller tests
  Acceptance test x86_cpu_model_versions: fix mismatches between test and messages
  Acceptance test x86_cpu_model_versions: shutdown VMs
  Acceptance test machine_m68k_nextcube.py: relax the error code pattern

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>